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Show 362 PROF. WESTWOOD ON THE GENUS PERGA. [May 4, be found added to the technical specific descriptions of these two insects. Many of the species are remarkable for metallic colours, which are of rare occurrence in the majority of the species of the family to which they belong. 1. PERGA DORSALIS. Perga dorsalis, Leach, Zool. M H C . iii. p. 117, 8 • 2 • Perga scutellata, Westw. in Griffith's Anim. Kingd. Ins. pl. 76. fig. 2, and pl. 106. fig. 3, vol. ii. pp. 402, 792. " P. ceeruleo-chalybeata; clypeo, labro, antennis, pleuris macula triangulari, thoracis angulis anticis, scutello pedibusque subfer-rugineo- luteis, abdomine supra macula magna quadrata sericea fiavida externe serrata; alis fulvescentibus, pterygosteorum margine stigmateque ferrugineis; mandibulee luteo-ferrugineee, latere interno nigricantes. Variat femoribus posticis apice nigris; abdomen postice sub august atum. Fcemina latet. Long. corp. 10^, exp. alar. 2\\ lin." (Leach.) Species permagna, maris abdomine macula magna quadrata sericea (segmenta media dorsalia occupante), alisque anticis stigmate magno, margine antico pone stigma oblique subtruncato; scutello in mare piano, in fcemina macula transversa breviori albida notato; abdomineque supra viridi-ceneo subnitido. Hab. in Australasia (Moretou Bay &c). In Mus. Hopeiano plurima individua utriusque sexus. The details of the structure of the female published from my drawings in Griffith's 'Animal Kingdom,' pl. 106, were copied by Guerin-Meneviile in his ' Iconograpbie du Regne Animal, Insectes,' pl. 64. fig. 2. Another figure of the female was published by Brulle (' Hist. Nat. Ins. Hym.' iv. pl. 48. fig. 1, p. 674) under the name of Perga scutellata, Leach. An account of the habits of this species, under the name of Perga eucalypti, was published by Messrs. Bennett and Scott in Proc. Zool. Soc. 1859, p. 209, (Annulosa) pl. 62, with figures of the larvae and of the female insect. The larvae were found living gregariously on the leaves of Eucalyptus citriodora and other species, as well as upon Callistemon, which they rapidly destroy. The larvae were huddled together both on the upper and under sides of the leaves, arranged, for the most part, in regular rows. When disturbed they bend their bodies in the form of an arch, and emit a greenish fluid from tbe mouth; they also emitted so powerful an odour of the leaves on which they had been feeding as to scent the room in which they were placed. When full-grown they are from 2-2^ inches long, of a uniform velvety black, with numerous short, stiff white hairs, and with only six large squamous reddish feet, apparently being destitute of the fleshy prolegs so common in the larvae of Tenthredinidae. When feeding, they keep the abdominal portion of their bodies in motion, rapping their extremities against the leaves. They bury themselves underground in October, forming brownish cocoons of |